docs: def cascaded_union(cls, vectors, dst_crs, prevalidate=False):
          # type: (list, CRS, bool) -> GeoVector
          """Generate a GeoVector from the cascade union of the impute vectors."""
          try:
              shapes = [geometry.get_shape(dst_crs) for geometry in vectors]
  
              if prevalidate:
                  if not all([sh.is_valid for sh in shapes]):
                      warnings.warn(
                          "Some invalid shapes found, discarding them."
                      )
  
          except IndexError:
              crs = DEFAULT_CRS
              shapes = []
  
          return cls(
              cascaded_union([sh for sh in shapes if sh.is_valid]).simplify(0),
              crs=dst_crs
          )